Engine system and method for controlling an engine

Abstract

Engine system, including: a motor body (10); an intake pipe (30) which is connected to an intake side of the main engine body (10); a mass flow sensor (32) which is provided in the intake pipe (30) and outputs a measured value of the amount of air flowing through the intake pipe (30); an exhaust pipe (40) which is connected to an exhaust side of the engine body (10); a removal device (41) provided in the exhaust pipe (40) which removes an air pollutant contained in an exhaust gas flowing through the exhaust pipe (40); a return line (50) that connects the exhaust side of the main engine body (10) to the intake pipe (30); a return valve (52) that controls the flow rate of the exhaust gas flowing from the return line (50) to the intake pipe (30); a regeneration control unit (605) that closes the return valve (52) to perform a regeneration process of the removal device (41); and an air quantity calculation unit (606) which calculates a theoretical value of an air quantity flowing to the intake side of the main engine body (10) based on a state quantity of the main engine body (10) during the regeneration process, characterized in that the motor system further comprises: a correction value calculation unit (610) which calculates a correction value to correct the measured value for each of three or more air volume ranges based on the measured value and the theoretical value during the regeneration process; a correction value storage unit (602) that stores the correction values ​​associated with each of the air volume ranges, wherein the ranges are defined by dividing a measurement range of the mass flow sensor (32) into three or more ranges; and a correction unit (604) that corrects the measured value using the correction value that is assigned to the area among the three or more areas to which the measured value belongs.

Description

Technical field

[0001] The present invention relates to a motor system and a method for controlling a motor. State of the art

[0002] In some housings, the engine is equipped with a mass flow sensor that measures the airflow on the intake side. A common type of mass flow sensor is a hot-wire sensor, which applies an electric current to a hot wire located in an intake manifold. This heats the wire, and the sensor measures the current flowing through the wire to determine the airflow. The air flowing through the intake manifold draws heat from the hot wire, and its resistance changes. The greater the airflow, the greater the heat drawn from the hot wire. Therefore, the mass flow sensor can measure the current flowing through the hot wire to determine the airflow.

[0003] It is known that, for example, in hot-wire mass flow sensors, dust contained in the air adheres to the hot wire, thereby degrading the measurement accuracy. JP 2001-107797A discloses a method in which a correction value for a measured value is calculated based on a mass flow sensor reading and the amount of intake air, which is calculated based on the engine speed and boost pressure when the engine is in a steady-state operating condition.

[0004] JP 2006 - 9 745 A relates to a method for correcting the output signal of an airflow sensor in an internal combustion engine equipped with exhaust gas recirculation (EGR), a particulate filter, and a turbocharger. With the EGR function deactivated, the expected fresh air quantity is calculated based on engine operating parameters and compared with the sensor signal. If the values ​​differ by more than a threshold value, the output signal of the airflow sensor is corrected accordingly.

[0005] DE 11 2012 006 284 T5 describes a method for controlling a diesel engine in which a correction value for an air mass flow sensor (MAF sensor) is determined based on a deviation between a NOx value estimated from engine speed and engine load and a NOx value measured in the exhaust gas. The exhaust gas recirculation valve (EGR valve), controlled by the corrected MAF signal, allows for more precise control of NOx reduction.

[0006] DE 199 50 146 A1 discloses a system for the online calibration of an air mass flow sensor (MAF sensor) in an internal combustion engine. Using a downstream condition sensor, an ideal air mass flow is determined and compared with the output signal of the MAF sensor during normal engine operation. Based on this deviation, calibration parameters are adjusted electronically. Recalibration is performed continuously by software routines without requiring the sensor to be disassembled or additional hardware to be used. Summary of the invention: Technical problem

[0007] In a case where the engine has an exhaust gas recirculation (EGR) system that recirculates a portion of the exhaust gas to the intake side, the amount of air flowing to the engine's intake side is represented by the sum of the amount of air drawn in from outside and the flow rate of the EGR system. Therefore, it is assumed that the correction value is precisely calculated by interrupting the recirculation of exhaust gas through the EGR system to match the amount of air flowing to the engine's intake side with the amount of air drawn in from outside.

[0008] In a case where exhaust gas recirculation is interrupted to calculate the intake air volume, it is necessary to calculate the intake air volume after the change in air volume caused by the interruption has stabilized. However, in a case where the vehicle is a work machine, such as a hydraulic excavator, it is unlikely that the steady state of the engine will persist for long during operation. Therefore, the possibility of calculating the correction value is reduced.

[0009] It is an object of the present invention to provide a motor system and a method for controlling a motor that can accurately correct a measured value from a mass flow sensor during the normal operation of a working machine. Solution to the problem

[0010] This problem is solved according to the present invention by providing a motor system with the features specified in independent claim 1 and a method for controlling a motor with the features specified in independent claim 6.

[0011] In particular, the engine system according to the present invention comprises: an engine body; an intake manifold connected to an intake side of the engine body; a mass flow sensor provided in the intake manifold and outputting a measurement of the amount of air flowing through the intake manifold; an exhaust manifold connected to an exhaust side of the engine body; a removal device provided in the exhaust manifold and removing an air pollutant contained in exhaust gas flowing through the exhaust manifold; a return line connecting the exhaust side of the engine body to the intake manifold; a return valve controlling the flow rate of exhaust gas flowing from the return line to the intake manifold; and a regeneration control unit closing the return valve to perform a regeneration process of the removal device.An air volume calculation unit that calculates a theoretical value of an air volume flowing to the intake side of the engine body based on a state quantity of the engine body during the regeneration process; a correction value calculation unit that calculates a correction value to correct the measured value for each of three or more air volume ranges based on the measured value and the theoretical value during the regeneration process; a correction value storage unit that stores the correction values ​​associated with each of the air volume ranges, the ranges being defined by dividing a measured value range of the mass flow sensor into three or more ranges; and a correction unit that corrects the measured value using the correction value assigned to the range among the three or more ranges to which the measured value belongs. Advantageous effects of the invention

[0012] According to the present invention, the motor system can accurately correct the measured value of the mass flow sensor during normal operation of the working machine. Brief description of the drawings Fig. Figure 1 shows a schematic diagram illustrating a configuration of a motor system according to a first embodiment. Fig. Figure 2 shows a schematic block diagram illustrating a configuration of an engine control unit according to the first embodiment. Fig. Figure 3 shows a diagram illustrating an example of information stored in a correction value storage unit according to the first embodiment. Fig. Figure 4 shows a diagram illustrating an example of the information stored in a sample storage unit according to the first embodiment. Fig. Figure 5 shows a flowchart illustrating the operation of the motor control according to the first embodiment. Fig. Figure 6 i shows a diagram illustrating a time series of MAF and MCF according to experimental results using the engine system. Fig. Figure 7 shows a flowchart illustrating a correction value update process according to the first embodiment. Fig. Figure 8 shows a diagram illustrating a relationship between the number of samples and a correction value according to the experimental results using the motor system. Fig. Figure 9 shows a diagram illustrating a procedure for updating the correction value in a case where the correction values ​​for two adjacent areas were updated in the first embodiment. Fig. Figure 10A shows a first diagram illustrating a relationship between a slope and a threshold value of the slope and a relationship to the correction value according to the first embodiment. Fig. Figure 10B shows a second diagram illustrating the relationship between the slope and the threshold of the slope and the relationship to the correction value according to the first embodiment. Fig. Figure 10C shows a third diagram illustrating the relationship between the slope and the threshold of the slope and the relationship to the correction value according to the first embodiment. Fig. Figure 11 shows a schematic block diagram illustrating a configuration of a computer according to at least one embodiment. Description of the embodiments<Erste Ausführungsform> <<Konfiguration des Motorsystems 1> >

[0013] The embodiments are described in detail below with reference to the drawings.

[0014] Fig. Figure 1 shows a schematic representation of a configuration of a motor system 1 according to a first embodiment.

[0015] The engine system 1 comprises an engine main body 10, a turbocharger 20, an intake pipe 30, an exhaust pipe 40, a recirculation pipe 50 and an engine control unit 60.

[0016] The main engine body 10 is a diesel engine in which a plurality of combustion chambers are provided. The main engine body 10 is equipped with an intake manifold 11, which distributes air to each combustion chamber, and an exhaust manifold 12, which collects the exhaust gases exiting each combustion chamber. The main engine body 10 is equipped with a speed sensor 101, which measures the rotational speed of the main engine body 10. The intake manifold 11 is equipped with a temperature sensor 121, which measures the temperature of the intake manifold 11, and a pressure sensor 122, which measures the pressure of the intake manifold 11.

[0017] The supercharger 20 increases the density of the air flowing into the main engine body 10 using the exhaust gas exiting the main engine body 10. The supercharger 20 comprises a turbine 21 in the exhaust pipe 40, a compressor 22 in the intake pipe 30, and a variable nozzle (not shown). A [missing information - likely a specific component] in the turbine 21 in Fig. The arrow shown indicates that the exhaust gas flow rate is variable. The compressor 22 is connected to and driven by the turbine 21. The compressor 22 is driven by the rotation of the turbine 21 to charge the intake air to the main engine body 10. Furthermore, the engine control unit 60 controls the opening degree of the variable nozzle to adjust the rotational speed of the turbine 21. In another embodiment, the compressor 20 may also include a fixed nozzle or an exhaust gas throttle valve instead of the variable nozzle.

[0018] The intake pipe 30 connects the outside air and the intake manifold 11 of the main engine body 10. In the intake pipe 30, an air filter 31, a mass flow sensor 32, the compressor 22 of the turbocharger 20 and an aftercooler 33 are arranged in the following order from the upstream side.

[0019] The air filter 31 filters the intake air using a filter and prevents the ingress of foreign objects, such as dust, into the main engine body 10.

[0020] The mass flow sensor 32 contains a hot wire (not shown) which is provided in the intake pipe 30. The mass flow sensor 32 applies a current through the hot wire to heat it and measures the amount of current flowing through the hot wire to measure the amount of air. That is, the mass flow sensor 32 measures the amount of outside air (mass air flow (MAF)) flowing into the intake pipe 30. The mass flow sensor 32 is also referred to as a MAF sensor.

[0021] The aftercooler 33 cools the air compressed by the charger 20.

[0022] The exhaust pipe 40 connects the exhaust manifold 12 of the engine body 10 to the outside air. The turbine 21 of the turbocharger 20 and a diesel particulate filter (DPF) 41 are located in the exhaust pipe 40 in the following order, starting from the upstream side.

[0023] The DPF 41 is a removal device for particles contained in the exhaust gases exiting the engine body 10. Solid particles are an example of air pollutants. The DPF 41, for example, has silicon carbide as its base material. The particles contained in the exhaust gas are captured as they flow through the pores formed in the DPF 41. The captured particles are combusted by the oxygen contained in the exhaust gas when the exhaust gas temperature reaches a level at which an oxidation reaction occurs. When the pores of the DPF 41 become saturated due to particle deposition, the particles are burned to renew the separation function of the DPF 41. The DPF 41 is equipped with a differential pressure sensor 411, which measures the differential pressure between the upstream and downstream sides of the DPF 41.

[0024] The return pipe 50 connects the exhaust manifold 12 of the engine body 10 and the intake pipe 30. The return pipe 50 draws a section of the exhaust gas from the exhaust manifold 12 and returns it to the intake pipe 30. The return pipe 50 includes a return cooler 51 and a return valve 52, in order from the upstream side. The return cooler 51 cools the exhaust gas from the exhaust manifold 12. The return valve 52 regulates the flow rate of the exhaust gas flowing from the return pipe 50 to the intake pipe 30. A [missing information - likely a specific component] in the return valve 52 in Fig. The arrow shown indicates that the degree of opening is variable.

[0025] The recirculation pipe 50 returns a portion of the exhaust gas to the intake manifold 11 (recirculation) to reduce the oxygen concentration in the intake air and thereby lower the combustion temperature of the engine body 10. This reduces the amount of nitrogen oxides contained in the exhaust gas. According to the first embodiment, both the exhaust pipe 40 and the recirculation pipe 50 are connected to the exhaust manifold 12. In another embodiment, however, the recirculation pipe 50 can be branched off from the exhaust pipe 40. <<Konfiguration der Motorsteuerung 60> >

[0026] The engine control unit 60 adjusts the fuel injection quantity, fuel injection timing, variable nozzle of the turbocharger 20, and the return valve 52 according to the actuation force of a device, such as an accelerator pedal (not shown), and the measured values ​​of various sensors for controlling the engine speed and torque. In this case, the engine control unit 60 corrects the measured value of the mass flow sensor 32 according to the deterioration. That is, the engine control unit 60 corrects the measured value of the mass flow sensor 32 according to a reduction in measurement accuracy caused by, for example, dust contained in the air adhering to the hot wire of the mass flow sensor 32. Furthermore, the engine control unit 60 determines, based on the measured value of the differential pressure sensor 411, whether the DPF 41 needs to be replaced or not, and performs a regeneration process on the DPF 41.

[0027] Fig. Figure 2 is a schematic block diagram showing the configuration of the motor control 60 according to the first embodiment.

[0028] The engine control unit 60 comprises a measured value acquisition unit 601, a correction value storage unit 602, a range specification unit 603, a correction unit 604, a regeneration determination unit 605, an air quantity calculation unit 606, an engine control unit 607, a sampling unit 608, a sampling value storage unit 609 and a correction value calculation unit 610.

[0029] The measurement acquisition unit 601 acquires measured values ​​from the mass flow sensor 32, the speed sensor 101, the temperature sensor 121, the pressure sensor 122 and the differential pressure sensor 411.

[0030] The correction value memory 602 stores a correction value for correcting the measured value of the mass flow sensor 32, i.e., the measured value of the air volume flowing through the intake pipe 30. Hereinafter, the measured value of the air volume flowing through the intake pipe 30 is also referred to as the MAF measured value. The correction value according to the first embodiment is obtained by dividing a theoretical value of the air volume flowing through the intake pipe 30 by the MAF measured value. Hereinafter, the theoretical value of the air volume flowing through the intake pipe 30 is also referred to as the theoretical MAF value. Furthermore, according to another embodiment, a correction value can be a value such as a deviation rate between the measured MAF value and the theoretical MAF value. The correction value memory unit 602 stores the correction values ​​in connection with three or more air volume ranges. Fig. Figure 3 is a diagram showing an example of the information stored in the correction value storage unit 602 according to the first embodiment. For example, as shown in Fig. As shown in Figure 3, the correction value storage unit 602 divides the MAF measurement range into six ranges and stores the correction values ​​in association with each of the six ranges.

[0031] The in Fig. 2 The area specification unit 603 shown specifies an air volume range to which the MAF measurement belongs, based on the MAF measurement acquired by the measurement acquisition unit 601.

[0032] The correction unit 604 corrects the MAF reading based on the correction value stored in the correction value storage unit 602. That is, the correction unit 604 multiplies the MAF reading by the correction value associated with the range specified by the range specification unit 603 to correct the MAF reading.

[0033] The regeneration determination unit 605 determines, based on the measured value of the differential pressure sensor 411 acquired by the measurement acquisition unit 601, whether a post-processing regeneration process should be carried out for the regeneration of the DPF 41. Specifically, the regeneration determination unit 605 estimates the amount of particulate deposits in the DPF 41 based on the measured value of the differential pressure sensor 411 and determines whether the post-processing regeneration process should be carried out if the amount of deposits exceeds a predefined threshold. Furthermore, the regeneration determination unit 605 can determine whether the post-processing regeneration process should be carried out if a predetermined time period has elapsed since the previous post-processing regeneration. The post-processing regeneration process is an example of the regeneration process of the DPF 41.

[0034] The air flow calculation unit 606 calculates the theoretical value of the mass charge flow (MCF) flowing to the intake side of the main engine body 10 based on the readings from the speed sensor 101, the temperature sensor 121, and the pressure sensor 122, which are acquired by the data acquisition unit 601. That is, the air flow calculation unit 606 calculates the theoretical MCF value based on the volumetric efficiency and the engine speed. Since the opening degree of the recirculation valve 52 is zero during the regeneration process after regeneration, the theoretical MCF value is equal to the theoretical value of the mass airflow (MAF) flowing through the intake manifold 30. Therefore, it can be said that the value calculated by the air flow calculation unit 606 during the regeneration process after regeneration corresponds to the theoretical MAF value.

[0035] The engine control unit 607 determines the fuel injection quantity, the opening degree of the variable nozzle of the turbocharger 20, and the opening degree of the return valve 52 based on the measured values ​​acquired by the data acquisition unit 601 from the speed sensor 101, the temperature sensor 121, and the pressure sensor 122, the MAF measured value corrected by the correction unit 604, and the theoretical MCF value calculated by the air flow calculation unit 606. The engine control unit 607 multiplies the theoretical MCF value calculated by the air flow calculation unit 606 by a predetermined return rate to determine the air flow rate of the return pipe 50. The engine control unit 607 determines the opening degree of the return valve 52 based on the determined flow rate.

[0036] However, the engine control unit 607 performs a control operation such that the opening degree of the recirculation valve 52 is zero during the regeneration process after processing, regardless of the flow rate. Therefore, it is possible to increase the oxygen concentration in the intake air and raise the combustion temperature. Furthermore, the control unit 607 operates the variable nozzle of the turbocharger 20 in such a way that the opening degree is very small when the engine body 10 is operating at low speed and low load, where the engine speed and torque are low. Therefore, it is possible to increase the pumping losses of the engine body 10 and raise the exhaust gas temperature.

[0037] The sampling unit 608 determines whether or not to sample the MAF measurement value before correction and the theoretical MCF value calculated by the air mass calculation unit 606 during the regeneration process of the engine control unit 607 after processing. The accuracy of the air mass calculation by the air mass calculation unit 606 is low when the main engine body 10 is in a non-steady state. Therefore, the sampling unit 608 determines whether to sample the MAF measurement value and the theoretical MCF value when the rate of change of the engine speed and the fuel injection quantity is sufficiently small.The sampling unit 608 calculates an average of the MAF measurements, an average of the theoretical MCF values, and the number of samples for each air volume range based on the information stored in the sampling unit 609, and stores the calculated values ​​in the sampling unit 609. Hereinafter, the average of the MAF measurements is referred to as an average MAF measurement, and the average of the theoretical MCF values ​​is referred to as an average theoretical MCF value.

[0038] The sample storage unit 609 stores the average MAF measurement, the average theoretical MCF value, and the number of samples so that they can be correlated. Fig. Figure 4 is a diagram showing an example of the information stored in the sample storage unit 609 according to the first embodiment.

[0039] The correction value calculation unit 610 calculates a correction value for each of a multitude of air volume ranges based on the information stored in the sample value storage unit 609. The correction value calculation unit 610 records the calculated correction value in the correction value storage unit 602. <<Bedienung der Motorsteuerung 60> >

[0040] The following describes the operation of the motor control unit 60 according to the first embodiment. Fig. Figure 5 is a flowchart illustrating the operation of the motor control unit 60 according to the first embodiment. When the motor system 1 starts up, the motor control unit 60 performs a step in each predetermined control cycle. Fig. The process is illustrated in Figure 5. First, the data acquisition unit 601 acquires measured values ​​from various sensors (step S1). Then, the range specification unit 603 specifies a range to which the MAF measured value acquired in step S1 belongs among the several ranges stored in the correction value storage unit 602 (step S2). The correction unit 604 reads the correction value belonging to the range specified in step S1 from the correction value storage unit 602 and corrects the MAF measured value (step S3). The airflow calculation unit 606 calculates the theoretical MAF value based on the measured values ​​of the engine speed and the intake manifold temperature and pressure 11 acquired in step S1 (step S4).

[0041] The regeneration determination unit 605 determines whether the operating mode of engine system 1 is a post-processing regeneration mode (step S5) or not. If the operating mode of engine system 1 is not the post-processing regeneration mode (step S5: NO), the regeneration determination unit 605 determines, based on the differential pressure measurement of the DPF 41 determined in step S1 (step S6), whether the post-processing regeneration mode should be started or not. The regeneration determination unit 605 can also determine whether the post-processing regeneration process should be started or not based on the time elapsed since the last post-processing regeneration process.In a case where the regeneration determination unit 605 decides not to start the post-processing regeneration process (step S6: NO), the control unit 607 generates control signals for the fuel injection quantity, the opening degree of the variable nozzle of the turbocharger 20, and the recirculation valve 52 based on various measured values ​​acquired in step S1, the MAF measured value corrected in step S3, and the theoretical MCF value calculated in step S4 (step S7). That is, the control unit 607 controls the engine system 1 in a normal operating mode. The engine control unit 60 then waits until the next control cycle.

[0042] On the other hand, if the operating mode of motor system 1 is the post-processing regeneration mode (step S5: YES) or if the regeneration determination unit 605 determines to start post-processing regeneration (step S6: YES), the control unit 607 generates a control signal to set the opening degree of the return valve 52 to zero (step S8). That is, the control unit 607 controls motor system 1 in the post-processing regeneration mode. Furthermore, the control unit 607 performs the control such that the opening degree of the variable nozzle of the compressor 20 is very small if the main motor body 10 is operating in a low-speed, low-load range where the motor speed and torque are low.

[0043] The scanning unit 608 then determines whether the starting conditions for the correction value calculation are met (step S9). According to the first embodiment, the starting conditions for the calculation are that a predetermined time interval has elapsed since the closing of the return valve 52, during which the temperature of the coolant is equal to or greater than a predetermined threshold (e.g., 72°C), the operating altitude is equal to or less than a predetermined altitude (e.g., 4600 m), and there is no fault in the components of the engine system 1 (e.g., the turbocharger 20, the return valve 52, the speed sensor 101, the temperature sensor 121, the pressure sensor 122, and the differential pressure sensor 411). Examples of component failure include the output of an abnormal value and a malfunction. The starting conditions for the calculation are not limited to these. In another embodiment, for example,The starting condition for the calculation is only the elapse of a predetermined time period since the closing of the return valve 52.

[0044] In a case where the starting conditions for the calculation are met (step S9: YES), the scanning unit 608 determines, based on the state of the engine system 1 (step S10), whether the scanning conditions for the MAF measurement and the theoretical MCF value are met. According to the first embodiment, the scanning conditions are that the engine system 1 is not accelerating, the operating range of the engine system 1 is not the low-speed and low-load range (the opening degree of the variable nozzle of the compressor 20 is not very small), the absolute value of the difference between the measured value and the target value of the intake manifold pressure 11 is equal to or less than a predetermined pressure deviation threshold, the rate of change of the engine speed is equal to or less than a predetermined threshold, and the rate of change of the fuel injection quantity is equal to or less than a predetermined threshold.In a case where the rates of change in engine speed and fuel injection quantity are calculated, it is preferable to apply a low-pass filter to the measured values ​​of engine speed and fuel injection quantity.

[0045] The following describes the reason why no scanning is performed in a case where the main motor body 10 is operated in the low speed and low load range. Fig. Figure 6 is a diagram showing a time series of the MAF measurement and the theoretical MCF value according to the experimental results using the engine system. Fig. Figure 6 shows a solid line as the MAF measurement value and a dotted line as the theoretical MCF value.

[0046] In a case where the main engine body 10 is operated in the low-speed and low-load range, a special operation is carried out which reduces the opening degree of the variable nozzle of the turbocharger 20 to a very small value in order to increase the pumping loss of the main engine body 10 in step S8. Therefore, as in Fig. Figure 6 shows that the error between the MAF measurement and the theoretical MCF value is greater in the low-speed and low-load range than in other ranges. Therefore, no sampling is performed in the low-speed and low-load range, where the error between the MAF measurement and the theoretical MCF value is large, in order to reduce sampling disturbances. Furthermore, for an engine where the error between the MAF measurement and the theoretical MCF value does not increase in the low-speed and low-load range, sampling can also be performed even when the engine is operating in the low-speed and low-load range.

[0047] The invention is not limited thereto. In another embodiment, e.g. in a case where the engine system 1 includes an exhaust gas throttle valve, the sampling conditions may further include that the opening degree of the throttle valve is equal to or less than a threshold value.

[0048] Referring again to Fig. 5. In a case where the sampling conditions are met (Step S10: YES), the sampling unit 608 updates the average MAF measurement, the average theoretical MCF value, and the number of samples based on the MAF measurement determined in Step S1, the theoretical MCF value calculated in Step S4, and the information stored in the sample storage unit 609, in conjunction with the range specified in Step S2 (Step S11). For example, the sample storage unit 608 updates the average MAF measurement, the average theoretical MCF value, and the number of samples in the following procedure.

[0049] The scanning unit 608 reads the average MAF measurement, the average theoretical MCF value, and the number of samples associated with the area specified in step S2 from the scanning unit 609. The scanning unit 608 updates the average theoretical MAF value m ave (t) according to the following expression (1), where t represents the current time. [Expression 1] mave(t)=n⋅mave(t−1)+m(t)n+1

[0050] Here, n indicates the number of samples stored in the sample memory unit 609. Furthermore, m indicates ave (t-1) represents the previous (time t-1) average measurement value stored in the sample storage unit 609. Furthermore, m(t) represents the MAF measurement value at time t.

[0051] The scanning unit 608 adds 1 to the number of samples to update the number of samples.

[0052] In another embodiment, all samples can be stored sequentially in the sample storage unit, and the average MAF measurement, the average theoretical MCF value, and the number of samples can be calculated. In this case, the sample unit 608 can calculate the average MAF measurement, the average theoretical MCF value, and the number of samples using the samples within 3σ of the standard deviation. The sample unit 608 stores the updated average MAF measurement, the updated average theoretical MCF value, and the updated number of samples in the sample storage unit 609.

[0053] If the conditions for starting the calculation or the sampling conditions are not met (step S9 or S10: NO), or if the sampling unit 608 updates the information stored in the sample storage unit 609 (step S11), the regeneration determination unit 605 determines whether the post-processing regeneration operating mode should be terminated or not (step S12). The regeneration determination unit 605 determines whether the post-processing regeneration operating mode should be terminated or not, for example, based on whether a predetermined time period has elapsed since the start of the post-processing regeneration and whether the DPF 41 has reached a predetermined temperature or not. In a case where the post-processing regeneration operating mode is not terminated (step S12: NO), the engine control unit 60 waits until the next control cycle.

[0054] In a case where the post-processing regeneration operating mode is terminated (step S12: YES), the correction value calculation unit 610 performs a correction value update process to update the correction values ​​stored in the correction value storage unit 602 (step S13). The correction value update process is described in detail below. When the correction value is updated, the correction value calculation unit 610 initializes the information stored in the sample value storage unit 609 (step S14). The motor control unit 60 then waits until the next control cycle.

[0055] According to the first embodiment, the engine control unit 60 can update the correction value during the post-processing regeneration, i.e., during the regeneration of the DPF 41. During the post-processing regeneration process, the opening degree of the recirculation valve 52 is always zero. Therefore, the steady-state holding time required for updating the correction value is shorter than in a case where, after the engine body 10 transitions to the steady state, the engine control unit closes the recirculation valve 52, waits for stabilization, and then updates the correction value.

[0056] As a result, the motor system 1 can accurately correct the measured value of the mass flow sensor 32 during the normal operation of a working machine. < <korrekturwertaktualisierungsprozess>>

[0057] The correction value update process is described below in step S13.

[0058] Fig. Figure 7 is a flowchart illustrating the correction value update process according to the first embodiment.

[0059] When the correction value calculation unit 610 starts the correction value update process, it selects the air volume ranges one after the other (step S51) and performs a process in the following steps S52 to S55 for the selected range.

[0060] The correction value calculation unit 610 determines whether the number of samples stored in the sample value storage unit 609, in connection with the range selected in step S51, is equal to or greater than a predefined sample number threshold (step S52). If the number of samples stored in connection with the range selected in step S51 is less than the sample number threshold (step S52: NO), the update of the correction value related to the range is suspended.On the other hand, if the number of samples stored in connection with the area selected in step S51 is equal to or greater than the sample count threshold (step S52: YES), the average theoretical MCF value stored in sample storage unit 609 in connection with the area selected in step S51 is divided by the average MAF measurement to calculate a correction value (step S53). Thus, the correction value is calculated for the area where a sufficient number of samples is guaranteed, thereby ensuring the reliability of the correction value.

[0061] Fig. Figure 8 is a diagram illustrating the relationship between the number of samples and the correction value according to the test results obtained using the motor system 1 according to the first embodiment. As shown in Fig. As shown in Figure 8, in a range where the number of samples is less than 200, the calculated correction value deviates significantly from the target correction value. Conversely, it can be seen that with a sample count of 200 or greater, the deviation from the target correction value is significantly reduced. Furthermore, it can be seen that the deviation of the calculated correction value in the vertical direction is small when the number of samples is 800 or greater, and that the calculated correction value is essentially equal to the target correction value when the number of samples is 1000 or greater. Therefore, the sample count threshold is preferably 200 or greater, more preferably 800 or greater, and most preferably 1000 or greater.

[0062] Referring again to Fig. 7. The correction value calculation unit 610 limits the calculated correction value to a value within a predefined permissible range (step S54). That is, if the calculated correction value is greater than the upper limit of the permissible range, the correction value calculation unit 610 updates the correction value to the upper limit. Furthermore, if the calculated correction value is less than the lower limit of the permissible range, the correction value calculation unit 610 updates the correction value to the lower limit.

[0063] The correction value calculation unit 610 updates the correction value stored in the correction value storage unit 602 in conjunction with the range selected in step S51 (step S55).

[0064] Then the correction value calculation unit 610 selects the areas for which the correction values ​​were not updated in steps S51 to S55, one after the other (step S56), and executes the process in the following steps S57 to S62 for the selected area.

[0065] The correction value calculation unit 610 indicates the number of areas for which the correction values ​​were updated in steps S51 to S55, specifically among the areas adjacent to the area selected in step S56 (step S57). In the Fig. In the example shown in step 3, the correction value calculation unit 610 determines, in a case where a range of 6 to 8 kg / min was selected in step S56, whether the correction values ​​were updated for both a range of 4 to 6 kg / min and a range of 8 to 10 kg / min, whether one of the correction values ​​was updated, and whether neither of the correction values ​​was updated. Furthermore, in the example shown in Fig. 3. Example shown in a case where a range of 16 to 18 kg / min was selected in step S56, the correction value calculation unit 610, whether the correction value for a range of 12 to 14 kg / min was updated or not.

[0066] In a case where none of the correction values ​​for adjacent areas have been updated (step S57: zero), the correction value calculation unit 610 does not update the correction value for the area selected in step S56 and retains the previous correction value.

[0067] Fig. Figure 9 is a diagram showing a method for updating correction values ​​in a case where the correction values ​​for two adjacent areas were updated according to the first embodiment. Fig. Figure 9 shows the correction value before the update in a black diagram and the updated correction value in a white diagram. Furthermore, in the white diagram, a white measurement point with a dotted contour line indicates a correction value obtained through interpolation.

[0068] In a case where the correction values ​​for two adjacent areas have been updated (step S57: two), the correction value calculation unit 610 calculates the correction value for the area using interpolation of the correction values ​​for the two adjacent areas (step S58). For example, as in Fig. Figure 9 shows that the correction value calculation unit 610 is determined in a case where a correction value is required for a range m b The update calculates an average of the correction values ​​for two adjacent areas m a and m c as a correction value for the range m b The correction value calculation unit 610 updates the correction value stored in the correction value storage unit 602 in conjunction with the range selected in step S56 (step S59).

[0069] In a case where the correction value for an adjacent area has been updated (step S57: one), the correction value calculation unit 610 calculates the slope of the correction value when the correction value is not updated, based on the previous correction value and the correction value for the one area (step S60). Specifically, the correction value calculation unit 610 calculates the slope d of the correction value when the correction value is not updated, using the following expression (2). d=(ka1−kb0) / (ma−mb)

[0070] Here there is k a1 the updated correction value with respect to the adjacent area. Furthermore, k indicates b0 the previous correction value for the range. Furthermore, m a the median flow rate of the adjacent area. Furthermore, m b the median flow rate of the area.

[0071] Then the correction value calculation unit 610 determines whether the absolute value d of the calculated slope is greater than a threshold value dk of the slope determined in the design (step S61) or not.

[0072] The Fig. 10A, Fig. 10B and Fig. Figure 10C are diagrams illustrating the relationship between the slope d and the threshold value dk of the slope, as well as the relationship to the correction value according to the first embodiment. In the Fig. In sections 10A to 10C, a black graph shows the correction value before the update, and a white graph shows the updated correction value. Furthermore, in the white graph, a white data point with a dotted contour line indicates the correction value calculated by extrapolation.

[0073] As in the Fig. 10A and Fig. As shown in Figure 10C, the correction value calculation unit 610, in a case where the absolute value of the slope d is greater than the threshold value dk of the slope (step S61: YES), calculates the correction value for the area using the extrapolation of the updated correction value for the adjacent area according to the sign of the slope d (step S62). Specifically, the correction value calculation unit 610, in a case where the sign of the slope, as in Fig. 10A, where negative, calculates the correction value kb1 for the range using the following expression (3). Furthermore, the correction value calculation unit 610 calculates in a case where the sign of the slope is positive, as in Fig. 10C shows the correction value kb1 for the range using the following expression (4). kb1=ka1−dk(|ma−mb|) kb1=ka1+dk(|ma−mb|)

[0074] Then the correction value calculation unit 610 updates the correction value stored in the correction value storage unit 602 in conjunction with the range selected in step S56 (step S63). However, in a case where the absolute value of the slope d is equal to or less than the threshold value dk of the slope, as in Fig. If 10B (Step S61: NO) is displayed, the correction value calculation unit 610 does not update the correction value for the range selected in step S56 and retains the previous correction value.

[0075] As previously described, according to the first embodiment, for a range with a sufficient number of samples from a multitude of airflow ranges, the motor control unit 60 divides the mean theoretical MCF value by the mean MAF measurement value to calculate the correction value. Therefore, it is possible to calculate the correction value while ensuring reliability. On the other hand, for a range with an insufficient number of samples, the motor control unit 60 updates the correction value using the correction values ​​for adjacent ranges. Therefore, it is also possible to calculate the correction value for the range with an insufficient number of samples. <Weitere Ausführungsformen>

[0076] One embodiment has been described in detail above with reference to the drawings. However, the specific configuration is not limited to the above, and, for example, the sequence can be modified in various ways. That is to say, in another embodiment, the order of the above-mentioned operations can be changed accordingly. Furthermore, some of the processes can be carried out in parallel.

[0077] The motor control unit 60 according to the embodiment described above can be configured by a single computer 90. Alternatively, the configuration of the motor control unit 60 can be distributed among several computers 90, and the several computers 90 can cooperate to function as the motor control unit 60. In this case, some of the computers 90 that constitute the motor control unit 60 can be located in the working machine equipped with the motor system 1, and the other computers 90 can be located outside the working machine.

[0078] The motor control unit 60, according to the embodiment described above, calculates the correction value for each of three or more air volume ranges. However, in other embodiments, the number of air volume ranges is not limited. For example, in another embodiment, the correction value can be calculated for two air volume ranges, or a correction value can be calculated independently of the air volume range.

[0079] Furthermore, according to the embodiment described above, the motor control unit 60 calculates the correction value for the range in which the number of samples is below the threshold value for the number of samples, based on the correction values ​​for other ranges adjacent to that range. In another embodiment, however, the calculation of the correction value is not limited to this. For example, according to another embodiment, a motor control unit 60 can calculate the correction value based on the mean value and the theoretical value, regardless of the number of samples.

[0080] Furthermore, a correction value calculation unit 610 according to another embodiment can be used instead of the one described in Fig. The correction value is shown in Table 3 as a function. The correction value can also be represented by a trained model. For example, according to another embodiment, a correction value calculation unit 610 can train a learning model that uses the MAF measurement as the input sample value and the theoretical MCF value as the output sample value to generate the trained model as the correction value.

[0081] Furthermore, according to the embodiment described above, the engine control unit 60 calculates the correction value during the regeneration process of the DPF 41. However, in another embodiment, the invention is not limited to this. For example, in a case where an engine system 1 according to another embodiment includes an SCR system (selective catalytic reduction system), the engine control unit 60 can calculate the correction value during the regeneration process of the SCR system. The SCR system is a device for removing nitrogen oxides from the exhaust gas. Nitrogen oxide is an example of an air pollutant. <Konfiguration des Computers>

[0082] Fig. Figure 10 is a schematic block diagram showing the configuration of computer 90 according to at least one embodiment.

[0083] The computer 90 contains a processor 91, a main memory 92, a storage 93 and an interface 94.

[0084] The motor control unit 60 is implemented in the computer 90. The operation of each of the aforementioned processing units is stored in memory 93 in the form of a program. The processor 91 reads the program from memory 93, loads the program into main memory 92, and executes the aforementioned process according to the program. Furthermore, the processor 91 allocates memory areas in main memory 92, corresponding to each of the aforementioned memory units, according to the program. Examples of processor 91 are a central processing unit (CPU), a graphics processing unit (GPU), and a microprocessor.

[0085] The program can be used to implement some of the functions of Computer 90. For example, the program can be combined with another program already stored in Memory 93, or with another program installed in a different device, to implement the functions. In another embodiment, Computer 90 can include, in addition to or instead of the configuration mentioned above, a custom large-format integrated circuit (LSI), such as a programmable logic device (PLD). Examples of PLDs include a programmable array logic (PAL), a generic array logic (GAL), a complex programmable logic device (CPLD), and a field-programmable gate array (FPGA). In this case, some or all of the functions implemented by Processor 91 can be implemented by the integrated circuit.The integrated circuit is also included in the example of processor 91.

[0086] Examples of memory 93 include an HDD (hard disk drive), an SSD (solid state drive), a magnetic disk, a magneto-optical disk, a CD-ROM (compact disc read only memory), a DVD-ROM (digital versatile disc read only memory), and a semiconductor memory.

[0087] The memory 93 can be an internal medium directly connected to a bus of the computer 90, or an external medium connected to the computer 90 via the interface 94 or a communication line. Furthermore, if this program is distributed to the computer 90 via the communication line, the computer 90, having received the distributed program, can extend the program in main memory 92 and perform the process mentioned above. In at least one embodiment, the memory 93 is a non-volatile physical storage medium.

[0088] Furthermore, the program can be used to implement some of the functions mentioned above. Additionally, the program can be a so-called difference file (difference program) that implements the aforementioned functions in combination with another program already stored in memory location 93. Industrial applicability

[0089] The motor system can accurately correct the measured value of the mass flow sensor during normal operation of the machine. Reference symbol list 1 engine system 10 Main engine body 30 Intake manifolds 32 Mass flow sensor 40 exhaust manifolds 50 Return line 52 Return valve Level 60 604 correction unit 606 Air volume calculation unit 610 Correction value calculation unit< / korrekturwertaktualisierungsprozess>

Claims

[1] Engine system, comprising: a motor body (10); an intake pipe (30) which is connected to an intake side of the main engine body (10); a mass flow sensor (32) which is provided in the intake pipe (30) and outputs a measured value of the amount of air flowing through the intake pipe (30); an exhaust pipe (40) which is connected to an exhaust side of the engine body (10); a removal device (41) provided in the exhaust pipe (40) which removes an air pollutant contained in an exhaust gas flowing through the exhaust pipe (40); a return line (50) that connects the exhaust side of the main engine body (10) to the intake pipe (30); a return valve (52) that controls the flow rate of the exhaust gas flowing from the return line (50) to the intake pipe (30); a regeneration control unit (605) that closes the return valve (52) to perform a regeneration process of the removal device (41); and an air quantity calculation unit (606) which calculates a theoretical value of an air quantity flowing to the intake side of the main engine body (10) based on a state quantity of the main engine body (10) during the regeneration process, characterized by , that the engine system further includes: a correction value calculation unit (610) which calculates a correction value to correct the measured value for each of three or more air volume ranges based on the measured value and the theoretical value during the regeneration process; a correction value storage unit (602) that stores the correction values ​​associated with each of the air volume ranges, wherein the ranges are defined by dividing a measurement range of the mass flow sensor (32) into three or more ranges; and a correction unit (604) that corrects the measured value using the correction value that is assigned to the area among the three or more areas to which the measured value belongs. [2] Engine system according to claim 1, wherein the correction value calculation unit (610) calculates the correction value based on the measured value and the theoretical value during the regeneration process for an area that meets predetermined conditions among the three or more areas, and calculates the correction value for an area that does not meet the conditions based on the correction values ​​for other areas adjacent to the area. [3] Motor system according to claim 2, wherein the correction value calculation unit (610) calculates the correction value for the area which does not meet the conditions among the three or more areas, based on the correction values ​​for two adjacent areas on either side of the area. [4] Motor system according to claim 2 or 3, wherein the correction value calculation unit (610) calculates a candidate correction value for the area that does not meet the conditions under the three or more areas, based on the correction values ​​for other areas adjacent to the area, and compares the candidate correction value with a previous correction value for the area to determine whether the candidate correction value or the previous correction value should be used as the current correction value for the area. [5] Motor system according to any one of claims 2 to 4, wherein the conditions include that the number of samples of the measured value belonging to the range is equal to or greater than a predetermined threshold. [6] A method for controlling an engine comprising an engine body (10), an intake manifold (30) connected to an intake side of the engine body (10), a mass flow sensor (32) provided in the intake manifold (30) which outputs a measurement of the amount of air flowing through the intake manifold (30), an exhaust manifold (40) connected to an exhaust side of the engine body (10), a removal device (41) provided in the exhaust manifold (40) which removes an air pollutant contained in an exhaust gas flowing through the exhaust manifold (40), a return line (50) connecting the exhaust side of the engine body (10) to the intake manifold (30), and a return valve (52) which controls a flow rate of the exhaust gas flowing from the return line (50) to the intake manifold (30), the method comprising the following steps: Closing the return valve (52) to perform a regeneration process of the removal device (41); and Calculating a theoretical value of an air quantity flowing to the intake side of the main engine body (10), based on a state quantity of the main engine body (10) during the regeneration process, characterized by that the procedure further includes the following steps: Calculating a correction value to correct the measured value for each of three or more air volume ranges based on the measured value and the theoretical value during the regeneration process; Storing the correction values ​​in connection with each of the air volume ranges, wherein the ranges are defined by dividing a measurement range of the mass flow sensor (32) into three or more ranges; and Correcting the measured value using the correction value assigned to the area among the three or more areas to which the measured value belongs.

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